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  1. Member
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    I did a test to compare a pro-sumer SVHS to a bog standard VHS and it seems the SVHS is only very slightly sharper. Chroma is still pretty bad. Is that normal?

    VHS:
    Image
    [Attachment 48197 - Click to enlarge]


    SVHS:
    Image
    [Attachment 48198 - Click to enlarge]


    I have a test card image that I can export direct to capture device for very clean output for the recorders.

    This is the workflow:

    SVHS:
    1. From photoshop,"Export Blackmagic Image.." to the Blackmagic Intensity Shuttle
    2. s-video cable from Blackmagic to Panasonic NV-HS930 (SVHS) in
    3. Record to S-VHS tape
    4. Then playback via s-video to Blackmagic Intensity Shuttle for capturing at uncompressed.

    VHS:
    1. From photoshop,"Export Blackmagic Image.." to the Blackmagic Intensity Shuttle
    2. composite cable from Blackmagic to Sharp VC-MH704 (VHS) in
    3. Record onto VHS tape
    4. Then playback via composite to Blackmagic Intensity Shuttle for capturing at uncompressed.

    Compared to a fairly high-end svhs recorder to a bog standard vhs, there doesnt seem much difference. And the svhs has rainbowing which isnt good.

    Is the SVHS player malfunctioning??

    Attached screenshots and huffy compressed video for you guys to view.
    Image Attached Files
    Last edited by Bassquake; 25th Feb 2019 at 09:34. Reason: Minor editing.
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  2. Yes, SVHS has the same chroma resolution as VHS. Only the luma resolution is improved -- easily seen in your sample images. And keeping the chroma and luma separate should prevent dot crawl and rainbow artifacts. Your SVHS cap also shows much better horizontal time base (less side-to-side jiggle of all those vertical edges).
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    Thanks jagabo. Although you say "keeping the chroma and luma separate should prevent dot crawl and rainbow artifacts", there's pretty significant rainbowing on the middle set of lines and none on the vhs one!

    Dont know how they could justify the price jump back in the day for marginal improvement!
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  4. aBigMeanie aedipuss's Avatar
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    vhs 240 lines of resolution. svhs 420 lines of resolution. ntsc tv analog broadcast tv 330 lines of resolution. svhs was quite an improvement at the time. if only they could have bumped up the chrominance level...
    --
    "a lot of people are better dead" - prisoner KSC2-303
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  5. Member dellsam34's Avatar
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    I get the rainbow effect on VHS not S-VHS, Either your BM device is doing something wrong or the quality of the S-VHS tape is no good, If you see the rainbow effect in the live feed then the best way to do this test is through a good quality HDMI to S-Video/Composite adapter using a blu-ray or a HD media player as a source.
    The quality depends on a lot of factors, The age of electronic components on the composite and S-Video circuit boards, The quality of the tapes, The quality of cables ...etc
    Also you get faithful results using the same VCR in VHS and S-VHS modes.
    Last edited by dellsam34; 25th Feb 2019 at 10:43.
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    Originally Posted by Bassquake View Post
    there's pretty significant rainbowing on the middle set of lines and none on the vhs one!
    You can't judge the quality of an entire standard by the performance of one vintage tape deck. Your Panasonic has an obvious problem with that particular range of frequencies. This could be due to a design flaw in the model, or more likely, aging/misadjustment of circuit board components.
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  7. Originally Posted by Bassquake View Post
    Thanks jagabo. Although you say "keeping the chroma and luma separate should prevent dot crawl and rainbow artifacts", there's pretty significant rainbowing on the middle set of lines and none on the vhs one!
    The lack of dot crawl and rainbow artifacts on your composite VHS cap indicates your capture device has a 3d comb filter. That can work very well on still parts of the picture (all of your video) but isn't as effective on moving parts of the picture. That comb filter will not be used the the s-video input as it shouldn't have those defects (ie crosstalk between the luma and chroma on a composite signal). I'm not sure why your s-video pattern has all that rainbowing. Was the tape recorded from a composite source rather than an s-video source? That might explain it.
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    Was the tape recorded from a composite source rather than an s-video source?
    Nope, was recorded from a pure s-video signal from the Blackmagic. I checked the output from the blackmagic to a tv and it looks excellent so its not the cables. The playback from the SVHS player is quite a drop in quality.

    The tape used in the SVHS player is a Konica SE-60 SVHS tape. Only been recorded onto twice.

    Edit: Image looks great when viewing live signal through SVHS player, just not the recording.
    Last edited by Bassquake; 25th Feb 2019 at 13:20.
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  9. Originally Posted by Bassquake View Post
    Was the tape recorded from a composite source rather than an s-video source?
    Nope, was recorded from a pure s-video signal from the Blackmagic. I checked the output from the blackmagic to a tv and it looks excellent so its not the cables. The playback from the SVHS player is quite a drop in quality.

    The tape used in the SVHS player is a Konica SE-60 SVHS tape. Only been recorded onto twice.
    If you view the s-video output from the SVHS deck on a TV do you see the same rainbowing? Maybe somebody who knows SVHS better than I do can explain it.
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  10. Member dellsam34's Avatar
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    Originally Posted by Bassquake View Post
    The tape used in the SVHS player is a Konica SE-60 SVHS tape. Only been recorded onto twice.

    Edit: Image looks great when viewing live signal through SVHS player, just not the recording.
    Try a good quality tape, I bet the rainbow effect will not be there, I get the same effect when recording S-VHS ET on poor quality tapes.
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    If you view the s-video output from the SVHS deck on a TV do you see the same rainbowing?
    If you mean playing the video on the svhs player then yes, the rainbow effect is still there. The live passthrough looks clean and no artifacts.

    Try a good quality tape
    I will give it a go. Might take a while to report back as I dont have another one on hand.
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    @dellsam34: Im not using SVHS ET by the way. Im using a standard Konica SVHS tape.
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  13. Member dellsam34's Avatar
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    Originally Posted by Bassquake View Post
    @dellsam34: Im not using SVHS ET by the way. Im using a standard Konica SVHS tape.
    That's my point, S-VHS ET is recording a S-VHS signal into a VHS tape = low quality S-VHS tape. I know the VCR does some tweaking to the signal but the point is that's what you get from tapes with low density particles such as low quality S-VHS tapes (in your case) or just plain VHS tapes (in my case) for such high band signal.
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  14. I imagine a poor s-video cable could allow the luma signal to leak into the chroma.
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  15. Member dellsam34's Avatar
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    Here is a sample of a S-VHS video recorded on a high quality tape, A raw version is available here without YouTube compression. Unfortunately I don't have a VHS version to compare to.

    Also I use something like this as a cable.
    Last edited by dellsam34; 25th Feb 2019 at 14:33.
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    @23dellsam34: Cool cheers. That looks a lot cleaner than my recordings. Maybe my player isnt working properly.

    I imagine a poor s-video cable could allow the luma signal to leak into the chroma.
    Looking at the live passthrough it looks nice and clean though, no rainbows. Tried swapping cables too.
    Last edited by Bassquake; 25th Feb 2019 at 14:47.
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    I noticed the VHS tape which had the test pattern recorded via composite, is better quality being played from the VHS player than the SVHS deck. I thought the SVHS player would keep the quality?

    Attached screencap of it. Compared side by side to the composite VHS.

    SVHS seems to have crosshatching noise (see cyan colour block) too.
    Image Attached Thumbnails Click image for larger version

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  18. Member Cornucopia's Avatar
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    @Bassquake,
    In looking at your 1st post, you aren't fully comparing apples to oranges. If you want a true indicator of whether you are getting a good recording from that deck, or at least whether the S- portion is better than the standard VHS portion, it would make more sense to make 4 recordings on the S-VHS deck:
    • Out via Composite, Record in S-VHS mode
    • Out via Composite, Record in VHS mode
    • Out via S-Video, Record in S-VHS mode
    • Out via S-video, Record in VHS mode
    Then you compare with the VHS deck (which I assume you are using that same composite for its one recording option).

    Also, you may be getting some comparison fudging by the fact that you are playing back via different decks, so you would also want to try playing each of those 5 recordings above through both the S-VHS deck and the standard VHS (knowing that the S- mode recordings may not playback properly or at all in the VHS deck if it doesn't have S- mode playback support). That way you can rule out what might be occurring from playback itself.

    ISOLATE the steps so you know what each element is contributing to the equation.

    Scott
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  19. Member dellsam34's Avatar
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    Using two VCR's is definitely not going to give you an accurate results.
    Like Cornucopia said, Use the same VCR and make two recordings from S-Video one in S-VHS on a good quality S-VHS tape and one in VHS mode on a good quality VHS tape, This is to test the medium recording capabilities.
    And two more recordings from composite, again one in S-VHS and one in VHS modes and this to compare the VCR processing capabilities, Just to see how the VCR handles the composite signal on both formats.

    From best to worst it should go like this:

    S-Video-S-VHS --> S-Video-VHS --> Composite-S-Video --> Composite-VHS
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  20. Originally Posted by Bassquake View Post
    I noticed the VHS tape which had the test pattern recorded via composite, is better quality being played from the VHS player than the SVHS deck. I thought the SVHS player would keep the quality?

    Attached screencap of it. Compared side by side to the composite VHS.

    SVHS seems to have crosshatching noise (see cyan colour block) too.
    It looks to me like the VHS deck has a noise reduction circuit. Along with with the noise it will reduce small low contrast detail. The SVHS deck may indeed have some other noise source. It's hard to find one in perfect working condition now since they haven't been made in many years.
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  21. Member
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    Originally Posted by Bassquake View Post
    I noticed the VHS tape which had the test pattern recorded via composite, is better quality being played from the VHS player than the SVHS deck. I thought the SVHS player would keep the quality?
    Have these machines been serviced and calibrated to specification? If not, you aren't getting a fair representation of the signal standards or quality of these models. You are just seeing the condition of this one particular Panasonic deck.
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  22. Member Cornucopia's Avatar
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    BingPot!

    Scott
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